This is part one of a series of blog posts discussing MIL-STD 810 Vibration Testing. This blog was written with reference to MIL-STD-810G w/Change 1 dated 15 April 2014. DES has the experience and expertise to help you determine what profiles are appropriate for your product and to run your MIL-STD-810 vibration test. Check out our vibration testing capabilities here.
MIL-STD-810 is a public military test standard that is designed to assist in the environmental engineering considerations for product design and testing. For the purposes of this blog series we will focus on Method 514.7, titled Vibration. This section defines the environmental vibration conditions a material or product may experience during the product life cycle and translates these conditions into replicable test procedures. Unfortunately, unless you’re familiar with this document, this section or any section for that matter may seem a little daunting. This blog will hopefully provide some guidance into navigating your way through it.
Figure 1. Table 514.7-I from MIL-STD-810G w/ Change 1
A customer contacted DES, seeking to create a reliability test plan for their product based on customer usage, new features and design limits. One of the concerns identified by the customer was the need for an accelerated life test which tested whether their “door assembly” product met the design specification for usage. In other words, the goal was to create an automated test solution which opened and closed cabinet doors to the estimated amount they would see during a lifetime in the field.
A customer approached DES looking to find an accelerated test solution for an AC powered cooling fan used in one of their products. The product had been established in the marketplace and the company was now looking for ways to reduce cost by looking at different cooling fan suppliers. Most fans, however, have a mean life rated for over 20,000 hours, so a typical accelerated life test would require a significant amount of time and money. Continue Reading Cooling Fan Reliability Testing Case Study →
You obtained quotes from a couple of vibration test labs. Your next task is to select a vibration test lab to perform your vibration test. Your selection should not be based upon price alone. Factors that should affect which lab you choose are capability, cost, timing, location, quality, and other special requirements. Continue Reading Choosing A Vibration Test Lab Part 2 →
Part 1 – Defining your project and Obtaining a Quote
Vibration testing is a very specialized field, not very well understood by many. There are different types of vibration and there are an enormous number of vibration test specifications. Vibration testing equipment is very expensive to purchase forcing many companies to hire a vibration test lab to fulfill their vibration testing requirements. So what should you expect when Choosing A Vibration Test Lab?
Product failures in HALT testing are defined as either the cessation of any functions or an out-of-specification condition for any performance characteristic. When a failure occurs, it is documented in DES’s HALT log. The exact time and test condition when each failure occurred is noted.
If the product fails to operate, the temperature or vibration will be changed toward ambient room conditions followed by a short dwell period to see if the product recovers. If the product is non-operational after dwelling at ambient conditions, trouble shooting will take place to find the failed component. The failed component will then be removed, repaired or replaced with a new component (as is practical) in an effort to expand the test stresses.
Figure 1 – Failure of Improperly Designed Mounting Tabs
HALT procedures vary from lab to lab but are typically performed similar to DES’s procedure which is summarized below. DES’s HALT procedure is divided into 5 Stages: Stage 1 – Temperature Step Stresses, Stage 2 – Temperature Ramps, Stage 3 – Vibration Step Stresses, Stage 4 – Combined Temperature &Vibration Stresses, and Stage 5 – Temperature Destruct Limits.
Stage 1 is used to determine the HALT Operational Limits for temperature. The goal is not to cause destruction in Stage 1, but sometimes the operational and destruct limits occur simultaneously. The HALT Destruct Limits for temperature and vibration are typically found in Stages 3 to 5.